/**
 * Copyright (c) 2005-2012 springside.org.cn
 */
package org.jbase.common.utils;

import java.io.UnsupportedEncodingException;
import java.net.URLDecoder;
import java.net.URLEncoder;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

import org.apache.commons.codec.DecoderException;
import org.apache.commons.codec.binary.Base64;
import org.apache.commons.codec.binary.Hex;
import org.apache.commons.lang3.StringEscapeUtils;

/**
 * 封装各种格式的编码解码工具类. 1.Commons-Codec的 hex/base64 编码 2.自制的base62 编码 3.Commons-Lang的xml/html escape 4.JDK提供的URLEncoder
 * 
 * @author calvin
 * @version 2013-01-15
 */
public class Encodes {

	private static final String DEFAULT_URL_ENCODING = "UTF-8";
	private static final char[] BASE62 = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz".toCharArray();

	/**
	 * Hex编码.
	 */
	public static String encodeHex(byte[] input) {
		return new String(Hex.encodeHex(input));
	}

	/**
	 * Hex解码.
	 */
	public static byte[] decodeHex(String input) {
		try {
			return Hex.decodeHex(input.toCharArray());
		} catch (DecoderException e) {
			throw Exceptions.unchecked(e);
		}
	}

	/**
	 * Base64编码.
	 */
	public static String encodeBase64(byte[] input) {
		return new String(Base64.encodeBase64(input));
	}

	/**
	 * Base64编码.
	 */
	public static String encodeBase64(String input) {
		try {
			return new String(Base64.encodeBase64(input.getBytes(DEFAULT_URL_ENCODING)));
		} catch (UnsupportedEncodingException e) {
			return "";
		}
	}

	// /**
	// * Base64编码, URL安全(将Base64中的URL非法字符'+'和'/'转为'-'和'_', 见RFC3548).
	// */
	// public static String encodeUrlSafeBase64(byte[] input) {
	// return Base64.encodeBase64URLSafe(input);
	// }

	/**
	 * Base64解码.
	 */
	public static byte[] decodeBase64(String input) {
		return Base64.decodeBase64(input.getBytes());
	}

	/**
	 * Base64解码.
	 */
	public static String decodeBase64String(String input) {
		try {
			return new String(Base64.decodeBase64(input.getBytes()), DEFAULT_URL_ENCODING);
		} catch (UnsupportedEncodingException e) {
			return "";
		}
	}

	/**
	 * Base62编码。
	 */
	public static String encodeBase62(byte[] input) {
		char[] chars = new char[input.length];
		for (int i = 0; i < input.length; i++) {
			chars[i] = BASE62[((input[i] & 0xFF) % BASE62.length)];
		}
		return new String(chars);
	}

	/**
	 * Html 转码.
	 */
	public static String escapeHtml(String html) {
		return StringEscapeUtils.escapeHtml4(html);
	}

	/**
	 * Html 解码.
	 */
	public static String unescapeHtml(String htmlEscaped) {
		return StringEscapeUtils.unescapeHtml4(htmlEscaped);
	}

	/**
	 * Xml 转码.
	 */
	public static String escapeXml(String xml) {
		return StringEscapeUtils.escapeXml10(xml);
	}

	/**
	 * Xml 解码.
	 */
	public static String unescapeXml(String xmlEscaped) {
		return StringEscapeUtils.unescapeXml(xmlEscaped);
	}

	/**
	 * URL 编码, Encode默认为UTF-8.
	 */
	public static String urlEncode(String part) {
		try {
			return URLEncoder.encode(part, DEFAULT_URL_ENCODING);
		} catch (UnsupportedEncodingException e) {
			throw Exceptions.unchecked(e);
		}
	}

	/**
	 * URL 解码, Encode默认为UTF-8.
	 */
	public static String urlDecode(String part) {

		try {
			return URLDecoder.decode(part, DEFAULT_URL_ENCODING);
		} catch (UnsupportedEncodingException e) {
			throw Exceptions.unchecked(e);
		}
	}

	public static String md5(String str) {
		return digest("MD5", str);
	}

	public static String sha1(CharSequence cs) {
		return digest("SHA1", cs);
	}

	public static String digest(String algorithm, CharSequence cs) {
		return digest(algorithm, StringUtils.getBytesUTF8(null == cs ? "" : cs), null, 1);
	}

	public static String digest(String algorithm, byte[] bytes, byte[] salt, int iterations) {
		try {
			MessageDigest md = MessageDigest.getInstance(algorithm);
			if (salt != null) {
				md.update(salt);
			}
			byte[] hashBytes = md.digest(bytes);
			for (int i = 1; i < iterations; i++) {
				md.reset();
				hashBytes = md.digest(hashBytes);
			}
			return fixedHexString(hashBytes);
		} catch (NoSuchAlgorithmException e) {
			throw Exceptions.unchecked(e);
		}
	}

	public static String fixedHexString(byte[] hashBytes) {
		StringBuffer sb = new StringBuffer();
		for (int i = 0; i < hashBytes.length; i++) {
			sb.append(Integer.toString((hashBytes[i] & 0xFF) + 256, 16).substring(1));
		}

		return sb.toString();
	}

	// public static String MD5(String str) {
	// String result = "";
	// try {
	// MessageDigest md = MessageDigest.getInstance("MD5");
	// md.update(str.getBytes());
	// byte b[] = md.digest();
	// int i;
	// StringBuffer buf = new StringBuffer("");
	// for (int offset = 0; offset < b.length; offset++) {
	// i = b[offset];
	// if (i < 0)
	// i += 256;
	// if (i < 16)
	// buf.append("0");
	// buf.append(Integer.toHexString(i));
	// }
	// result = buf.toString();
	// } catch (NoSuchAlgorithmException e) {
	// throw Exceptions.unchecked(e);
	// }
	// return result;
	// }

	public static String md5(String str, boolean isShort) {
		if (isShort)
			return md5(str).substring(8, 24);
		return md5(str);
	}
}
